I'm assuming it was Berry Plastiglas, same as Berry Mini-T shown below.

This optional seat cover looks similar to the Berry seat below.Maybe just another variation due to different calendar year?The Berry ad mentions an aluminum seat frame but the frameon the factory seat is steel.

Forum member "Sixteen Grand Sedan #56" was kind enough to turn me on to one of the original GM racing seats about 13 years ago. My seat was never used and had the GM part number on a piece of masking tape between the cover and the shell padding. Though my original GM racing seat looks very similar to the first item posted by Jon, the cover is slightly different. My cover extends over the steel bracing on the upper backside of the seat.

About 8 years ago I sourced some replicas of these original GM racing seats, and took some pictures of one next to a Shelby R-model seat. I took the pictures because several folks thought the GM piece was the same, or close, to a Shelby R-model seat. I think these pictures illustrate just how different these seat shells really are.

Early on, some guys such as Craig Fisher just fabricated side bolsters to fit around the stock seat.Of note, in '67 all Trans-Am cars needed to retain a passenger seat. For the '68 season (and after)the passenger seat no longer needed to be installed.

You know Chad, when I first looked at those seats I thought the same thing, they look just like a Shelby seat, but you are obviously correct, there are a lot of differences. When I was checking on the seat used in Gurney's Cuda I found out it was custom made but it looked like a Shelby seat that was modified, they raised the back quite a bit and had the metal reinforcement structure glassed' into it, but not high enough for a headrest...those were attached to the roll cages individually like the Mustangs. The Nickey seat looks like the one used in the BRE Datsun.

When Rick Stevens and I purchased that ex Alfie Ruys de Perez 69 camaro T/A car in 72, it had one of those Donohue Racemark seats - quite unlike anything I had seen previously and bears no resemblance to any of the above seat photos. It was like a fg container for your body - no padding. Jon probably has a photo of one?

I've got one of the Yenko or Nickey style seats that I got out of an IMSA RS Gremlin. If someone is looking for one of these seats, it pays to look around at various old race cars for sale on ebay or other sites as sometimes the seller will do a trade or sell the seat by itself. That's what happened with the seat I got. As for a Racemark "Donohue" seat, I don't have any photos of one handy. If somebody else does, please go ahead and post it. To me, they really look out of place in these cars but they were in fact used in a few old Trans-Am cars starting in 1970.

I've also attached a horribly old, low quality scan of a Racemark ad for these seats. When I get the chance to find my old pamphlet of Racemark, Fypro and Mark Donohue Performance Products, I'll surely take some better scans.

Thanks for posting that, Chad. Would you mind posting some photos of your aluminum replica GM seat that Steve Sunshine did for you and me a few years ago. I was pleased with how those turned out. They are a nice option for someone who can't located an original GM/Berry seat or who prefers the durabilty of the aluminum unit.